This invention relates to a clamping device for pressing several plate-shaped semiconductor components against a heat sink.
Such a clamping device is described in German Open Application (Deutsche Offenlegungsschrift) No. 29 26 403.
In the cooling of semiconductor components, good heat transfer between the semiconductor components and a heat sink is of decisive importance. In order to keep the heat transfer resistance low, the semiconductor components are generally pressed against the heat sink. This can be done, for instance, by bolting the semiconductor components directly to the heat sink by means of projecting tabs. In general, electrical contact as well as thermal contact is established between the semiconductor components and the heat sink. By directly bolting the semiconductor components to the heat sink, however, no uniform contact pressure is obtained, with the result that heat dissipation by such an arrangement is limited. Furthermore, the screw connection of each individual semiconductor component in the assembly is relatively cumbersome.
The above-mentioned German application discloses a clamping device, especially for disc-shaped thyristors for facilitating the dissipation of greater amounts of heat energy, wherein a semiconductor component rests against a heat sink at least on one side. Two clamping bolts are provided, between which a leaf spring is arranged. With this leaf spring, the semiconductor component is pressed against the heat sink, a contact piece being arranged between the leaf spring and the semiconductor component for uniform pressure distribution. With this clamping device, very uniform pressure of the semiconductor component against the heat sink is achieved, and also large contact pressures can be realized. Several series-connected semiconductor components can be stacked up and provided with a common clamping device. For independent or parallel-connected semiconductor components, however, a separate clamping device must be provided for each element. Because of the high cost of the clamping device as well as the cumbersome assembly, such a device is of interest only for high power chips.
An object of the present invention is to provide an improved clamping device of the above-described type wherein manufacturing of the device and installation of the semiconductor components are simplified. Another object of the present invention is to provide such a clamping device wherein several semiconductor components connected independently of or parallel to each other can be installed in a common clamping device in a space-saving manner.